MPEG-7 binary format for XML data

Abstract

Summary form only given. For the MPEG-7 standard, a binary format for the encoding of XML data has been developed that meets a set of requirements that was derived from a wide range of targeted applications. The resulting key features of the binary format are: high data compression (up to 98% for the document structure), provision of streaming, dynamic update of the document structure, random order of transmission of XML elements as well as fast random access of data entities in the compressed stream. To provide these functionalities, a novel, schema-aware approach was taken that exploits the knowledge of standardized MPEG-7 schema. The XML schema definition is used to assign codes to the individual children of an XML element. These codes are signalled in binary format to select nodes in the XML description tree. The binary format bit stream is organized as a sequence of access units. Each access unit can be decoded independently and contains information about a fragment of the description (fragment payload) and where to place the fragment in the current tree (context path). Compared to the standard text compressor ZIP, or the XML-optimized tool XMill, the MPEG-7 binary format achieves a 2-5 times better compression of the document structure and provides additional functionalities. These increase the flexibility and make it useful in broadcast applications and scenarios with limited bandwidth.